Abstract
Summary
Genetically obese (fatty) and lean rats were treated with several doses of estradiol-17β. The uterus of the untreated fatty rats was significantly smaller than the uterus of the lean rats. The uterine weight of castrated lean or fatty rats increased in weight after treatment with 0.1 or 1.0 μg/ day of estradiol-17β, but doses of 10 or 100 μg/day produced no further effect. Although castration lowered the uptake of radioactive iodine by the thyroid of lean rats, it was still significantly higher than in the thyroid of fatty rats. Thyroidal uptake of radioiodine also increased with estrogen treatment in both groups but the lean animals were more sensitive. We concluded that the small uterus in the fatty rat may be due to decreased estrogenization and that this may also partly account for the small pituitary and low thyroidal uptake of radioiodine.
Supported in part by Grant Nos. Am 15165, RR 00425, and HDO-5687. The authors thank Ms. P. Peterson and D. Yu for their excellent technical assistance.
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